DR MICHAEL MOSLEY: Carbs aren’t the enemy… but ditch that pasta

It may be a new year, but it seems the same old arguments are still raging about carbs.

‘Blow to low-carb diets’, ran some headlines last week, in the wake of a World Health Organisation-backed study that found people who eat the most wholegrain bread, grains and pulses – foods rich in fibre, and also carbohydrate – have the lowest risk of heart disease, stroke and bowel cancer.

The study’s author, Professor Jim Mann of the University of Otago in New Zealand, also hit out at ‘fashionable’ low-carb diets, popularised by celebrities.

The findings come after a report in August which suggested that those who stick to very low-carb diets, mainly of meat and animal fats – such as the keto, or ketogenic diet, and Atkins diet – die four years younger, on average, than those who eat even large amounts of carbs. Moderate intake, however, was linked with the best longevity.

But the supporters of low-carb eating can point at another huge study called Pure, published in 2017, which looked at the dietary habits of more than 135,000 people in 18 countries, which concluded that ‘high carbohydrate intake was associated with a higher risk of total mortality.’

In other words, lots of carbs are bad. So where does the truth lie?

FIRST… A LESSON IN CHEMISTRY 

Carbs, mostly, come in three forms in the average diet.

First there are sugars, made up of single molecules of glucose, fructose and sucrose.Table sugar, for instance, is typically 50 per cent glucose, 50 per cent sucrose. Maple syrup is a mix of sucrose, with some glucose and fructose, and water. And so on.

Then there are starchy foods, which include bread and potatoes, but also rice, pasta and breakfast cereals.

These starchy foods are made up of long chains of glucose molecules that get broken down in our guts and released as glucose into our blood.

Depending on how highly processed they are, these foods either contain a lot of healthy fibre, or not much.

Then there are fruits, vegetables and pulses – like lentils – which contain varying amounts of carbs, but also contain fibre.

Fibre is actually a form of carbohydrate which our bodies can’t digest, but which is great for feeding the microbiome, the two to three pounds of microbes that live in the gut and which are so important for the immune system and overall health.

Ever since the agricultural revolution thousands of years ago, carbs have formed the basis of most people’s diets. Fruits, vegetables and starchy foods are cheap and filling, and an immediate source of energy. These sorts of carbs made the modern world possible.

And yet, obesity has spiralled over the past few decades. Today, about 26 per cent of adults are obese – of a weight that raises the risk of a range of health problems, including diabetes, heart disease and some cancers. That’s risen from 15 per cent in 1993. More worryingly, one in ten five-year-olds is now obese.

So, what has changed? Well, there is no single scientific answer. However, many people argue that we eat more in general – snacking, for instance, is a very modern phenomenon – and particularly consume more sugary foods.

Public Health England’s National Diet and Nutrition Survey suggests that Britons, on average, eat more than three times the recommended 30g a day of ‘free’ sugars – that’s sugar added to foods, or found in syrups and fruit juices, and so easily absorbed and laid down as fat.

It is also easier to live a more sedentary life than it was for generations before us. The real argument rages around foods like white rice, pasta and potatoes.

These foods don’t contain a lot of nutrients, and little fibre, but they do have a lot of starch. Studies have found that eating a standard portion of white rice, potatoes or spaghetti has a similar effect on blood sugar levels as eating seven to ten teaspoons of sugar.

So, what does this all mean? Well, not all carbs are equal.

And while a diet consisting of moderate levels of fibrous wholegrains and pulses will be beneficial, a diet rich in refined starchy carbs won’t be.

WHAT ABOUT LOW-CARB WEIGHT-LOSS PLANS?

WHEN it comes to short-term weight loss, there have been a number of studies showing that cutting down on all carbs is an effective way to shed the pounds. But, when the low-carb dieters in these studies are followed up years later, most have regained the weight they had lost.

The same goes for low-fat dieters who eat lots of refined carbs. But those who eat a balanced, Mediterranean-style diet lose weight and keep it off, according to research. They also benefit from lower ‘bad’ cholesterol and blood sugar levels.

So what’s in this kind of diet? Not much in the way of pizza, pasta, rice or potatoes, but lots of olive oil, nuts – also a good source of fibre – oily fish, and vegetables, and plenty of whole grains, beans and lentils, which are also high in carbs, albeit ‘healthy’ ones.

Given the choice between a very low-carb, a low-fat or a Mediterranean diet, particularly when it comes to long-term benefits, I think the scientific evidence is overwhelmingly in favour of the latter.

If you want to lose weight fast, or get your blood sugars under better control, then your best approach may be to start off with a low-calorie, low-carb Med-style diet until you have achieved your goals, then add in more grains and fibre for the long-term benefits this will bring to your microbiome, and therefore to you.

You’ll find more information and menus at thefast800.com.

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